A 32oz bottle is $6-8 at Walmart. It goes a pretty good ways, just add until you get a pretty fishy smell from the sprayer.

As far a as the residual smell in the tank, I didn't notice a problem once it was rinsed, I noticed it more with the milk than the emulsion, but neither really caused a problem in my opinion.

I actually stumbled up on this by accident. Last year the deer were hammering my SH as it was coming up and I was afraid they were going to kill it before it got going good. I had been reading about milorganite for years but hadn't tried it. I was going to go that route but was at my mother's helping her in the garden and she uses the fish emusion as a fertilizer in her organic garden and the smell was very strong while she was spraying. So I began to think that this would most likely repel deer, because it sure was repelling me at the time she was spraying it. So I decided to give it a try and it seemed to work perfectly for me. I only sprayed once and it kept the deer off of it for about 2-3 weeks and then I began to notice a the deer traffic starting to pick back up after that time. That was just enough time, was very cost effective, and it was easy to put out since I was going to be spraying anyway at that time...